Personally I would like a Goblin DLC (Playable Goblins, Hobgoblins, Bugbears and Kobolds (and yes, Kobolds are related to goblins in the lore) all in 1 pack),
Playable Aasimar DLC, pretty much speaks for itself,
Eberron DLC (Artificer class like Gortash, Playable races like Kalashtar (Psionic Humans), Shifters (Half-Werewolves), Changelings (Like Orin the Red) and Warforged, you and your companions are transported to Eberron from Faerun by a wizard or through a spelljammer),
Curse of Strahd for a Helloween themed DLC, for those that don't know it's set in Ravenloft instead of Faerun,
Also a Drizzt DLC,
Just have a DLC where you can watch Astarion (and by association Neil Newbon) fanboy to Drizzt Do'Urden in a similar fashion as Karlach and Jaheira,
